Mount files from a code host

Created by: Piszmog

Mounting paths in a batch spec steps in #31790 (closed) (src-cli) and #31792 (batch changes server-side) requires a User to upload files/directories from their local machine. Being able to mount files/paths from a code host would help to version control and share files more easily.

Things to consider,

• impacts to caching
• how to display the code host files in the UI (storing in DB vs directly from code host)
• impacts to src-cli and batch changes server-side implementations
• Determine if changes are needed to the mount structure or a specific format is needed for path